"The economy is still on shaky ground and many workers continue to be worried about losing their jobs despite the fact that annual layoffs are at the lowest level since the late 1990s," Chief Executive Officer John Challenger said.

Worries about losing a job are pushing sick workers to go into work, "where the sick worker is not only performing at a reduced capacity but also likely to infect others," Challenger said.

Along with the health consequences, U.S. employers are out an average of $10.4 billion in direct costs during each flu season, the Centers for Disease Control and Prevention has estimated.

That price tag does not include lost productivity, but only direct costs of hospitalizations and other doctor bills.

By the numbers, this flu season -- although it is not over -- has been far more expensive this year than last, as 15,000 cases of the flu have been reported, more than three times the 4,400 cases reported in the last flu season, the outplacement firm reported Wednesday.

For the current season 29 out of 41 states reporting data on the season have described the number of flu cases this year as "severe."

Challenger urged companies to have "an effective leave policy," and he urged employees to take advantage of that if possible.

"While sick employees may think they are doing the right thing by 'toughing it out' and coming into work when ill, the fact is they are only making matters worse," he said.

"Whether it is motivated by job security or a desire to continue making a contribution in an overburdened workplace, presenteeism, as it has come to be called, only spreads illness to more workers and further damages the employers ability to meet demand," he added in a statement.

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